What feature helps to prevent the cooling of sprinkler heads in hangars?

The feature that helps to prevent the cooling of sprinkler heads in hangars is draft curtains. Draft curtains are physical barriers that can redirect air movement within a space, effectively creating separated zones. In hangars, where large doors may frequently open and close, the introduction of cold air can lower the temperature around sprinkler heads. By utilizing draft curtains, warm air can be retained in the areas where the sprinkler heads are located, ensuring that they remain functional and at the proper temperature for activation in the event of a fire. This prevention strategy is crucial in aviation facilities to maintain safety standards and ensure rapid response from fire suppression systems.

Other options, like high-pressure water jets and external heating systems, do not specifically address the issue of air movement around sprinkler systems. Regular maintenance checks are essential for ensuring the functioning of the entire fire suppression system, but they do not directly affect the cooling of the sprinkler heads due to drafts or cold air entering the hangar. Thus, draft curtains serve a unique and necessary role in this context.